import React, { PureComponent } from "react";

export default class App extends PureComponent {
  state = {
    a: "xiaoming",
  };
  render() {
    console.log("render");
    return (
      <div>
        {this.state.a}
        <button onClick={() => this.setState({ a: "xiaozheng" })}>
          点击改变
        </button>
      </div>
    );
  }
}
